Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Typical Hem bend process capability

Typical Hem bend process capability

Typical Hem bend process capability

Hi Folks,

I'm looking into incorporating a hem bend into a sheet metal part and I'm trying to understand typical process capability that is expected when this form is created in manufacturing. Currently, our manufacturing facility doesn't have the tooling to perform the operation so we can't do any studies so i'm hoping this group could provide some insight.

I'm working with 2mm thick sheet metal and what we're really trying to understand is what the typical tolerance would be on the hem bend flange as it is bent 180deg onto itself.

Appreciate all and any feedback.


RE: Typical Hem bend process capability

The hem is really just like any other bend, it is made by first bending an acute angle (tighter than 90) and then hitting that same bend with flat tooling to complete the bend. Because of this tolerances will be similar to other bends. Typical values we use are +/- 0.015" bend to edge and +/- 0.020" bend to bend. These would apply only to coined hems, not ones with larger radii and a space in the hem flange. What kind of hem are you looking for?

RE: Typical Hem bend process capability

Thanks, hendersdc. We're looking at doing a coined hem bend or what I've heard described as a closed hem bend.

The insight you provided aligns with what we were looking at, which is encouraging. Thanks :)

RE: Typical Hem bend process capability

Are you hemming a panel to provide a cosmetic edge/edge protection, or are you actually bonding two panels together?

You may want to investigate robotic roller hemming if you are talking moderate or high volumes.

RE: Typical Hem bend process capability

Hint: If you look real close at a hem, even a coined one, you will see a teardrop or circular opening at its root, usually at least .005" diameter, so you can't really get a hem as thin as twice the material thickness. Sometimes that matters.

Mike Halloran
Pembroke Pines, FL, USA

RE: Typical Hem bend process capability

Great feedback, thanks everyone! This definitely helps :)

RE: Typical Hem bend process capability

Make sure when you do this, to select tooling that allows the hemmed edge to overlap the die by at least 2 times the thickness of the part, If you do not , you may notice strange discrepancies in the dimensioning of the hemmed part due to its not gripping the edge of the die as the angle forms.

You are judged not by what you know, but by what you can do.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. Download Now
eBook - Integrating the Engineering Ecosystem
Aras Innovator provides multiple options for integrating data between systems, depending on the scenario. Utilizing the right approach to meet specific business requirements is vital. These needs range from authoring tools, federating data from various and dissimilar databases, and triggering processes and workflows. Download Now
Research Report - Simulation-Driven Design for SOLIDWORKS Users
In this engineering.com research report, we discuss the rising role of simulation and the paradigm shift commonly called the democratization of simulation. In particular, we focus on how SOLIDWORKS users can take advantage of simulation-driven design through two analysis tools: SOLIDWORKS Simulation and 3DEXPERIENCE WORKS. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close